Removable casing construction



Oct. 10, 1967 w` H|GN|TE 3,345,826

REMOVABLE CASING CONSTRUCTION Filed July 29, 1965 3 Sheets-Sheet l R N kwm s 4 1H w. S R o m L .WA

.M n ww/ Oct. l0, y1967 w. HIGNITE 3,345,826

Filed July 29, 1965 3 Sheets-Sheet 2 REMovABLE cAsING CONSTRUCTION bwa KI l I4', x2] BY WALTER H 6 `ns 7mm .staf/@ Affannevs INVENTOR.

United States Patent O 3,345,826 REMOVABLE CASING CONSTRUCTION WalterHignite, Milwaukee, Wis., assignor to Wisconsin Caisson, Inc.,Milwaukee, Wis., a corporation of Wiscousin Filed July 29, 1965, Ser.No. 475,762 4 Claims. (Cl. 61-53) This invention relates to removablecasing construction and has been employed in removable casing used incaisson and cemented piles.

Casing of this nature generally consists of a series of interlockedtubular joints which are driven into the ground following drillingoperations and then successively removed as the hole is filled withcement.

Threaded couplings for such casing joints are time consuming for bothinstallation and removal of the casing.

The present invention provides an interlock between the joints of casingthat greatly facilitates dropping of the casing in the hole andsubsequent removal.

The invention utilizes a bel-l and spigot type of connection between thejoints and which is generally constructed by welding a cylindrical ringor skirt of larger diameter to one end of each joint and which isadapted to receive the opposite end of the next joint for a suitabledistance.

Interlocking of the joints is accomplished by a bayonet type connectioncomprising a radial peg secured inwardly of the ring and a generallyL-shaped slot in the edge of the spigot member of the next succeedingjoint to receive thepeg.l t

All of the L-shaped slots should be orientated in the same direction sothat as the casing is lowered into the hole following attachment ofeachsuccessive joint the entire assembly may be rotated in a directionthat will move each peg in its corresponding slot circumferentially tothe dead end of the horizontal portion of the slot where by the jointsare interlocked ivertically with one another.

A driver cap is Vprovided for similar interlock in the ring at the upperend of each successive upper joint as the casing is dropped in the hole.

, Generally the driver c ap consists of a dummy cylindrical section withthe corresponding interlocking slot and having a central drive portionfor receiving the rotary drive member -and for driving downwardly wherenecessary. y

After such` a casing is installed it is gradually filled with concreteto complete a pile. lFor-this purpose it is desir'l able to remove thecasing progressively as the cement be-A comes set yso that the casing isretrieved for repeated use.

Where an Lshaped slot is employed in the cap dif- Patented Oct. 10, 1967lCe showing a hole partially filled wit-h concrete and with the upperjoint of casing being lifted from the string;

FIGURE 2 is a detail section showing the interlocking connection betweentwo joints;

FIGURE 3 is a detail elevation taken on line -3-3 of FIG. 2;

FIGURE 4 is a side elevation of a driver cap partly in section andshowing a T-s'lot therein;

l FIGURE 5 is a plan view of the driver cap;

FIGURE 6 is a perspective vievv of the driver cap; and

FIGURE 7 is a detail perspective view showing the clamp for holding thestring of casing against loss in the hole while adding or removing ajoint at the upper end of the string.

Referring to FIGURE l of the drawing the hole 1 has been drilled in theearth as shown, to a suitable depth and are raised free from the hole atthe top.

ticulty arises in removal of the casing during cementing since afterlifting the casing to free the upper joints at the top of the hole areverse turning of the driver cap will not necessarily free theinterlock between the upper joint and the nextsucceeding joint so as topermit removal. Instead the cap is often released from the upper jointand the latter remains interlocked to t-he string' of casing.

To overcome this ditlculty the present invention provides a T-slot inthe driver cap so that upon reversal in rotation the peg in the slotwill move to the opposite dead end and then force the peg at the lowerend of the Vupper joint to move into line' with the lvertical portion oft-he L-shaped slot to vertically release the upper joint for lifting bythe cap. i

The cap also has one or more vertical openings therei through for thepouring of cement into the string of casing without removing the drivercap for each pouring.

The accompanying drawings illustrate the best mode presentlycontemplated by the inventor for carrying out the invention.

In the drawings:

FIGURE 1 is a vertical section of a portion of ground 'Each joint 4 inthe embodiment illustrated has a skirt 5 welded to its upper end andextending beyond thesame to receive the lower endof the next successivejoint.

One or more interlocking pins or pegs'6 extend inwardly from the skirt Sand are adapted to be received in corresponding L-shaped slots 7 in thelower end o f the connecting joint when the latter is inserted into theskirt. The horizontal portions 8 of slots 7 extend in thesamecircumferential direction from the vertical portions 0f the slots sothat when the string of casing is assembled by adding successive jointsat the top as the casing is lowered vin the hole, the added joint -isturned or rotated in a direction tocause the pegs 6 to enter thehorizontal portions 8 of thev corresponding slots 7. Generally thestring will be slowly rotated in the same direction as it drops inthehole so that the interlock will be maintained at all times. l v

The lower end of the lowermost joint 4 will be provided with a skirt 9having a cutting edge 10 which is effective to facilitate lowering whenthe string is thus rotated.

The casing is supported at the top by a clamp 11 which is placed aroundthe upper joint which extends partially in the hole, and engages. thelower edge of the skirt 5 to limit or prevent the downward movement ofthe string 3 when it is desired to add or to remove a joint at the top.A casing cap 12 is employed to serve as the driving, lifting andlowering connection for the casing; For this purpose cap 12 has'arcylindrical skirt portion 13 simulating the lower end of a joint andhaving slots 14 'positioned to receive the corresponding pegs 6 on ajoint 4 and to enter the skirt 5 carrying the pegs.

The cap 12 has a closure plate 15 with radial strength- 'ening members16 rigidlyV securing the skirt 13 to a central collar 17 whichpreferably has a square opening to receive a square drive shaft 18 todrivethe same rotationally. Y

A removable `pin 19 is insertable transversely through the collar 17 andshaft 18 to secure the same together so that vertical movement of shaft18 will effect corresponding vertical movement of the casing interlockedwith the cap 12.

The slots 14 are T-shaped to provide adequate interlock of the cap 12with the adjacent joint 4 regardless of the direction of rotation of thecap.

Thus, in lowering a string of casing the cap 12 is attached to the upperend of the first joint 4 and lifted by a suitable cable hooked to one ofthe members 16 which has a hole 20 therein for receiving the cable hook.When the cap 12 and its joint 4 are located over the hole the driveshaft 18 is lowered into collar 17 and pin 19 inserted therethrough. Thecable is then unhooked from cap 12 and drive shaft 18 slowly lowers thejoint 4 into the hole while turning it in a direction tending to retainthe pegs 6 in the horizontal portion 21 of the T-slots 14, until theskirt 5 rests upon clamp 11.

Then the cap 12 is rotated back to register the pegs 6 with the verticalportions of the corresponding T-slots whereupon the cap is lifted offthe joint. The cap is then applied to the next successive joint 4 andpositioned to drop the same into the upwardly extending skirt 5 of thejoint already in the hole. Slow rotation of the second joint in thedirection that effects interlock of the lower end thereof will cause thepegs 6 in the first skirt S to enter the L-shaped slots 7 and theportions 8 thereof in the lower end of the second joint. Then the clamp11 is removed and the string dropped into the hole by lowering cap 12with shaft 18 while rotating the assembly in a direction maintainingpegs 6 of the iirst joint in the horizontal portions 8 Kof slots 7 inthe second joint and pegs 6 of the second joint in the correspondinghorizontal portions of slots 14 in cap 12.

Successive joints may be added to the string of casing 3. in the samemanner as described for the second joint above.

The hole 1 is generally filled with cement 2 in successive steps whereina given depth of cement is poured generally corresponding to the lengthof a joint so that the casing string 3 may be raised one joint at a timeand successive pouring operations may await adequate setting of theconcrete in the next previous pouring.

By providing one or more openings 22 in the cap plate 15 it is possibleto pour a batch of cement into the casing without removing the cap 12.If members 16 are adequately secured to skirt 13 and Collar 17 the plate15 can be entirely eliminated. However, the plate is useful in generallypreventing dropping of foreign items into the casing and hole.

In lifting the casing, when each successive upper joint is fully aboveground the clamp 11 is disposed beneath the skirt 5 of the next lowerjoint to support the string in the hole. Then cap 12 is rotated in areverse direction by shaft 18 to release the pegs 6 of the skirt 5 thatis supported on clamp 11 from the L-shaped slots 7 in the lower end ofthe upper joint. During this rotation the pegs 6 of the upper joint willmove in the horizontal portion of the corresponding T-slots 14 in skirt13 `of cap 12 to the opposite end of the slot portion so that the capwill remain vertically interlocked with the upper joint.

After release of the interlock between the upper joint and the string,the pin 19 is removed, the shaft 18 is raised froml collar 17 and thecable is secured to the cap and the latter is lifted to carry and removethe upper joint `away `from the string. Then the cap is disconnectedfrom the removed joint and attached to the joint at the top of thestring and shaft 18 is secured in collar 17.

The removal of successive joints in this manner continues until theentire string of casing is removed.

If desired the skirt of the driver cap 12 may be reinforced by a ring`23 welded thereto on the inside of the lower edge and which bridges theslots 14 and prevents deformation of the skirt 12 in use.

The T -slots 14 in cap 12 when employed with L-shaped slots 7 in thejoints greatly facilitates lifting and removal of successive casingjoints by preferentially maintaining a vertical interlock between thecap and the upper joint while rotating the same in a reverse directionfor disconnecting the upper joint from the casing string.

Various modes of carrying out the invention are contemplated as beingwithin the scope of the following claims particularly pointing out anddistinctly claiming the subject matter which is regarded as theinvention.

I claim:

1. The combination in a string of casing of a plurality of casing jointseach having a skirt at its upper end receiving the lower end of theadjacent joint, a bayonet connection between adjacent joints comprisingat least one inwardly extending peg in the skirt and an invertedL-shaped slot in the end of the adjacent joint and receiving thecorresponding peg, the horizontal portions of all of said invertedL-shaped slots extending in the same circumferential direction from thevertical portions thereof, and a driver cap for manipulating the stringof casing and for successively adding joints thereto and removing jointstherefrom, said driver cap having a skirt simulating the lower end of ajoint and adapted to enter the skirt on the upper end of any joint andto removably interlock therewith both rotationally and vertically, saidcap skirt having a T-shaped slot therein for receiving eachcorresponding peg in said joint skirt to maintain the vertical interlocktherewith for either direction of rotation of the driver cap.

2. The construction of claim 1 in which said driver Cap has one or moreopenings therethrough for the pouring of concrete into said casingstring without removal of the cap therefrom.

3. The construction of claim 1 in which said driverv cap has areinforcing ring welded inside the lower edge of the skirt thereof.

4. The combination in a vertical string of casing of a plurality ofcasing joints having loose bell and spigot interconnections therefor,the adjacent joints being rotationally and vertically interlocked by apeg extending radially from the upper end of `one member of theinterconnection and disposed in an inverted L-shaped slot in the lowerend edge of the cooperating member of the interconnection, thehorizontal portions of said slots extending in the circumferentialdirection of rotation of the casing whereby the pegs are normallyretained seated in said horizontal portions and retain the jointsagainst vertical separation, and a driver cap for manipulating thestring of casing and for successively adding joints thereto and removingjoints therefrom, said driver cap simulating the lower end of a jointand adapted to interconnect with the upper end of any joint, said caphaving a T- shaped slot in the lower edge thereof for receiving eachcorresponding peg of the upper end of a casing joint to maintain thevertical interlock therewith for either direction of rotation of thedriver cap.

References Cited UNITED STATES PATENTS 2,693,343 ll/l954- Darin et al.175--321 FOREIGN PATENTS 30,324 10/1959 Finland. 162,023 1/ 1958 Sweden.

DAVID J. WILLIAMOWSKY, Primary Examiner. JACOB SHAPIRO, Examiner.

1. THE COMBINATION IN A STRING OF CASING OF A PLURALITY OF CASING JOINTSEACH HAVING A SKIRT AT ITS UPPER END RECEIVING THE LOWER END OF THEADJACENT JOINT, A BAYONET CONNECTION BETWEEN ADJACENT JOINTS COMPRISINGAT LEAST ONE INWARDLY EXTENDING PEG IN THE SKIRT AN AND INVERTEDL-SHAPED SLOT IN THE END OF THE ADJACENT JOINT AND RECEIVING THECORRESPONDING PEG, THE HORIZONTAL PORTIONS OF ALL OF SAID INVERTEDL-SHAPED SLOTS EXTENDING IN THE SAME CIRCUMFERENTIAL DIRECTION FROM THEVERTICAL PORTION THEREOF, AND DRIVER CAP FOR MANIPULATING THE STRING OFCASING AND FOR SUCCESSIVELY ADDING JOINTS THERETO AND REMOVING JOINTSTHEREFROM, SAID DRIVER CAP HAVING A SKIRT SIMULATING THE LOWER END OF AJOINT AND ADAPTED TO ENTER THE SKIRT ON THE UPPER END OF ANY JOINT ANDTO REMOVABLY INTERLOCK THEREWITH BOTH ROTATIONALLY AND VERTICALLY, SAIDCAP SKIRT HAVING A T-SHAPED SLOT THEREIN FOR RECEIVING EACH